It is well known for extrusion pulling apparatus to incorporate guide means for tracking the extrusion pulling jaws along the extrusion pulling axis. Further, the guide means typically incorporate a plurality of rollers for movement of the extrusion pulling apparatus along the guide means. Typically, the rollers and guide means are mounted either below, or above the extrusion pulling apparatus and provide the sole means for stability and support for the extrusion pulling apparatus.
The Mannell U.S. Pat. No. 3,881,339 (issued May 6, 1975) discloses an extrusion puller comprising an elongated rectangular rail with a carriage moveable along said rail on several sets of rollers. The rollers roll on the rectangular rail on the top, bottom and side surfaces for guiding the extrusion puller along the extrusion axis.
The Zazimko, et al. U.S. Pat. No. 4,079,616 (issued Mar. 21, 1978) discloses a draw bench for producing cylindrical tubular items. A roller mounted carriage is mounted on a set of rollers to traverse the drawing axis.
An extrusion pulling apparatus with the guide means mounted above the extrusion puller is disclosed in Best U.S. Pat. No. 4,628,719 (issued Dec. 16, 1986). The guide means are essentially an inverted W-shape cross-section wherein the rollers of the extrusion puller are inserted into the bight portions of the inverted W-shaped guide means and supported on an inward extending flange. Rollers are incorporated on the extrusion puller for tracking along the flanges.
Another example of an upper mounted guide means is found in Carraher et al. U.S. Pat. No. 3,585,833 (issued Jun. 22, 1971). A pair of I-shaped beams are mounted such that rollers of the extrusion puller are supported by the flanges of the I-shaped beam.
Other patents which disclose the use of a roller and guide means construction similar to those previously discussed include Caswall, J. R. et al. U.S. Pat. No. 4,313,329 (issued Feb. 2, 1982); Elhaus U.S. Pat. No. 4,507,950 (issued Apr. 2, 1985); and Nearman U.S. Pat. No. 3,580,183 (issued May 25, 1971).
It is also known in the prior art to utilize an I-beam as the guide means for the extrusion pulling apparatus. Rollers are mounted for rolling contact on a horizontal face of the I-beam and provide support for the extrusion pulling apparatus. In addition, rollers are mounted on the underside of the flanges of the I-beam to provide stability and tracking for the extrusion puller.
It is important to construct an extrusion puller which is extremely stable to avoid irregularities in the extruded/pulled material. A common source for such irregularities is a slip or studder in the extrusion puller apparatus. Therefore, an apparatus which decreases the frequency of slips or studders in the extrusion puller will increase the productivity of the extrusion pulling apparatus.